【摘要】 本文简要地综述了我国廿多年来,特别是近五年中稀土在钢中应用的科研和生产情况.经过大量试验,已有一批含稀土钢投入生产.实践证明,稀土元素能有效地改善低碳、低合金钢的横向韧性,改善高合金钢的热加工性能,提高电热合金丝的使用寿命,以及改善合金结构钢的低温韧性及回火脆性,提高钢材的疲劳寿命.稀土在改善钢的铸态组织、减少铸件和铸坯内裂纹等方面也得到一定应用.稀土的加入方法,早先采用炉内及包内投入法,回收率低,钢材性能不稳,且易造成浇注水口结瘤和低倍夹杂缺陷.近期研究成功的锭模内吊挂法、钢包内压入法,以及利用稀土渣的电渣重熔法等有较好效果,已在生产上应用.与此同时,研究水口结瘤的本质,提出了减轻或避免结瘤的冶炼浇注工艺.概述了稀土在钢中作用的机理.认为稀土在钢中基本的作用是净化及夹杂物变质作用.同时,也不能忽视稀土在合金化方面的作用.尽管稀土在钢中的固溶量甚微,但其在晶界的富集以及与钢中杂质的交互作用,会显著影响钢的有关性能.作者对稀土在钢中应用的前景提出了看法.更多还原

【Abstract】 A general review of the use of rare earth metals (REM) in steelmaking in China for the past 20 years is presented.Through large amount of research work and industrial trials, steels containing RE have been produced. Practice shows that REM additives improve transverse impact toughness and ductility of low carbon and low alloy steels, improve hot workability of high alloy steel and increase service life of resistance alloy wires, improve low temperature impact toughness and temper brittleness of structural alloy steels, prolong fatigue life of steel products. REM also find application in improving as-cast structure and decreasing cracking tendency of steel castings and contincast slabs.In the early days, REM additives were simply thrown into furnaces or ladles, resulting in low REM recovery rate, ladle nozzle blocking during teeming, instability of steel properties and macrodefects. The nature of nozzle blocking had been studied and the measures for lightening or avoiding nozzle blocking were adopted. At present, methods of hanging REM rods in ingot moulds and plunging the REM additives into ladles are in common use. The RE addition in the form of RE-oxide as slag ingredient in electroslag refining process has been proved successful and is now being used in production.The mechanism of the effects of RE on steel properties is also described. To date, REM is chiefly added to control inclusion shape and to give cleaning effect. The problem of alloying effect of RE should not be overlooked, although solid solubility of RE in steel is very low. It might be thought that the segregation of RE at grain boundaries and the interreaction between RE and tramp elements or alloying elements in steel may give rise to certain effects to the properties of steel.Finally, the outlook for the use of REM in steel industry is also described.更多还原